2 fields together being unique?

[freelance84]

I have two fields in a table:

comment and type

 

I have found that i now require that the combined result of comment and type needs to be unique.

i.e

different comments can be the same if their type's are different and, different types can be the same if their comment is different. But not combined.

 

Is this possible?

[tgeorge06]

I'm not an expert, but I used something like you are talking about to check and make sure my username was unique before having people register.

 

$query = mysql_query ("SELECT * FROM table WHERE comment='$comment'");
$numrows = mysql_num_rows($query);
if ($numrows == 0) 
{
//Do whatever
}else{
//Comment Not unique!
}

 

[freelance84]

Yea i could write some php to check the uniqueness before allowing the data to be inputted. But i was hoping there might be some way of setting this feature from the mysql table.

 

Say,

 

UNIQUE SPAN comment, type

 

(something like that)

[fenway]

You can have a unique index constraint across multiple columns.

[freelance84]

unique index constraint,

 

it's always the correct term i can never get my head to search for.

 

Thanks fenway